The major aim of this proposal is to study at the genetic, chemical and molecular level the antigen profile of the human lymphoid cell surface membrane and thus to gain a better understanding of its crucial role in defense and recognition of disease. It is expected that the elucidation of those structural and molecular features which determine the biological functions of human histocompatibility (HL-A) antigens will contribute toward a better understanding of this phenomenon. Specifically, it is hoped that such information will also facilitate the recognition of some of the structural changes in cell membranes which contribute to the characteristic disordered proliferations of neoplastic cells. It is anticipated that an evaluation of the genetic and molecular level of interrelations between HL-A antigens, beta2-microglobulin and tumor-associated antigens as well as several antigen receptors will provide a working basis to gain a better comprehension of the complex interplay among lymphoid cell surface antigens. We will evaluate the effect of virus induced transformations of cells on the expression of HL-A and tumor-associated antigens to determine whether viral genomes can code for or induce expression of these antigens and whether structural relationships exist between them. Finally, we hope that by establishing detailed chemical and molecular profiles of soluble HL-A antigens and by evaluating their capacity to evoke humoral and cellualr immune responses we will gain a better recognition at the molecular level of some control and regulatory aspects of the immune response.